Having a molecular structure comprising an ether bond rich in toughness and a phenylene group rich in rigidity and heat resistance, poly(aryl ketone)s represented by poly(ether ether ketone) (hereinafter PEEK for short) are crystalline thermoplastic resins excelling in heat resistance, flame retardancy, chemical resistance, dimensional stability, mechanical properties, etc. The poly(aryl ketone)s have very large fiber-reinforcement effects, and excel in thermal stability as well. For this reason, they are finding a wider range of applications as electric and electronic components, precision device components, automotive parts, etc. However, the poly(aryl ketone)s, albeit being high-performance resins, have found only limited applications because of their high prices. Besides, the poly(aryl ketone)s have processing temperatures of generally as high as about 390 to 410° C. and allowable ranges for processing conditions remain narrow with the addition of fibrous fillers thereto.
On the other hand, poly(arylene sulfide)s (hereinafter PAS for short) represented by poly(phenylene sulfide) (PPS for short) are crystalline thermoplastic resins excelling in heat resistance, flame retardancy, chemical resistance, dimensional stability, mechanical properties, etc., finding a wider spectrum of applications as electric and electronic components, precision device components, automotive parts, etc. PPS costs less than does the poly(aryl ketone). However, PAS has only limited applications in high temperature endurance fields because it is lower than the poly(ether ketone) in terms of crystal melting point, glass transition temperature and deflection temperature under load.
To improve the processability of the poly(aryl ketone), an alloy comprising PAS blended with the poly(aryl ketone), i.e., a resin composition has been proposed in the art (U.S. Pat. No. 4,684,699). This resin composition is lower in processing temperature and better in balances among physical properties than the poly(aryl ketone). With the poly(aryl ketone) and PAS, it is still difficult to obtain any resin composition having satisfactory mechanical properties such as tensile strength and bending strength, because they are less compatible with each other.
Resin compositions in which carbon fibers, glass fibers, potassium titanate fibers or ceramic fibers are added to an alloy comprising the poly(ether ketone) and PPS resins have also been put forward in the art (JP-A's1-282252, 1-282253, 1-282254 and 1-182255). However, these resin compositions, too, are found to have no sufficient mechanical properties because the poly(aryl ketone) and PAS are less compatible with each other.